Mohammed Aldosary
University of California, Riverside
Network
Latest external collaboration on country level. Dive into details by clicking on the dots.
Publication
Featured researches published by Mohammed Aldosary.
Nature Communications | 2016
Junxue Li; Yadong Xu; Mohammed Aldosary; Chi Tang; Zhisheng Lin; Shufeng Zhang; Roger K. Lake; Jing Shi
Pure spin current, a flow of spin angular momentum without flow of any accompanying net charge, is generated in two common ways. One makes use of the spin Hall effect in normal metals (NM) with strong spin–orbit coupling, such as Pt or Ta. The other utilizes the collective motion of magnetic moments or spin waves with the quasi-particle excitations called magnons. A popular material for the latter is yttrium iron garnet, a magnetic insulator (MI). Here we demonstrate in NM/MI/NM trilayers that these two types of spin currents are interconvertible across the interfaces, predicated as the magnon-mediated current drag phenomenon. The transmitted signal scales linearly with the driving current without a threshold and follows the power-law Tn with n ranging from 1.5 to 2.5. Our results indicate that the NM/MI/NM trilayer structure can serve as a scalable pure spin current valve device which is an essential ingredient in spintronics.
Applied Physics Letters | 2016
Chi Tang; Mohammed Aldosary; Zilong Jiang; Houchen Chang; Benjamin Madon; Kyle Chan; Mingzhong Wu; Javier E. Garay; Jing Shi
A layer-by-layer epitaxial growth up to 227 atomic layers of ferrimagnetic insulator yttrium iron garnet (YIG) thin films is achieved on (110)-oriented gadolinium gallium garnet substrates using pulsed laser deposition. Atomically smooth terraces are observed on YIG films up to 100 nm in thickness. The root-mean-square roughness is as low as 0.067 nm. The easy-axis lies in the film plane, indicating the dominance of shape anisotropy. For (110)-YIG films, there is well-defined two-fold in-plane anisotropy, with the easiest axis directed along [001]. The Gilbert damping constant is determined to be 1.0 × 10−4 for 100 nm thick films.
Applied Physics Letters | 2016
Mohammed Aldosary; Junxue Li; Chi Tang; Yadong Xu; Jian-Guo Zheng; Krassimir N. Bozhilov; Jing Shi
30-80 nm thick yttrium iron garnet (YIG) films are grown by pulsed laser deposition on a 5 nm thick sputtered Pt atop gadolinium gallium garnet substrate (GGG) (110). Upon post-growth rapid thermal annealing, single crystal YIG(110) emerges as if it were epitaxially grown on GGG(110) despite the presence of the intermediate Pt film. The YIG surface shows atomic steps with the root-mean-square roughness of 0.12 nm on flat terraces. Both Pt/YIG and GGG/Pt interfaces are atomically sharp. The resulting YIG(110) films show clear in-plane uniaxial magnetic anisotropy with a well-defined easy axis along 〈001〉 and a peak-to-peak ferromagnetic resonance linewidth of 7.5 Oe at 9.32 GHz, similar to YIG epitaxially grown on GGG. Both spin Hall magnetoresistance and longitudinal spin Seebeck effects in the inverted bilayers indicate excellent Pt/YIG interface quality.
APL Materials | 2018
Chi Tang; Bin Cheng; Mohammed Aldosary; Zhiyong Wang; Zilong Jiang; Kenji Watanabe; T. Taniguchi; Marc Bockrath; Jing Shi
Quantum anomalous Hall state is expected to emerge in Dirac electron systems such as graphene under both sufficiently strong exchange and spin-orbit interactions. In pristine graphene, neither interaction exists; however, both interactions can be acquired by coupling graphene to a magnetic insulator as revealed by the anomalous Hall effect. Here, we show enhanced magnetic proximity coupling by sandwiching graphene between a ferrimagnetic insulator yttrium iron garnet (YIG) and hexagonal-boron nitride (h-BN) which also serves as a top gate dielectric. By sweeping the top-gate voltage, we observe Fermi level-dependent anomalous Hall conductance. As the Dirac point is approached from both electron and hole sides, the anomalous Hall conductance reaches ¼ of the quantum anomalous Hall conductance 2e2/h. The exchange coupling strength is determined to be as high as 27 meV from the transition temperature of the induced magnetic phase. YIG/graphene/h-BN is an excellent heterostructure for demonstrating proximity-...
Physical Review B | 2017
Junxue Li; Guoqiang Yu; Chi Tang; Yizhou Liu; Zhong Shi; Yawen Liu; Aryan Navabi; Mohammed Aldosary; Qiming Shao; Kang L. Wang; Roger Lake; Jing Shi
Electrical currents in a magnetic insulator/heavy metal heterostructure can induce two simultaneous effects, namely, spin Hall magnetoresistance (SMR) on the heavy metal side and spin-orbit torques (SOTs) on the magnetic insulator side. Within the framework of the pure spin current model based on the bulk spin Hall effect (SHE), the ratio of the spin Hall-induced anomalous Hall effect (SH-AHE) to SMR should be equal to the ratio of the field-like torque (FLT) to damping-like torque (DLT). We perform a quantitative study of SMR, SH-AHE, and SOTs in a series of thulium iron garnet/platinum or Tm3Fe5O12/Pt heterostructures with different Tm3Fe5O12 thicknesses, where Tm3Fe5O12 is a ferrimagnetic insulator with perpendicular magnetic anisotropy. We find the ratio between measured effective fields of FLT and DLT is at least 2 times larger than the ratio of the SH-AHE to SMR. In addition, the bulk SHE model grossly underestimates the spin torque efficiency of FLT. Our results reveal deficiencies of the bulk SHE model and also address the importance of interfacial effects such as the Rashba and magnetic proximity effects in magnetic insulator/heavy metal heterostructures.
Scientific Reports | 2018
M. Evelt; Christopher Safranski; Mohammed Aldosary; V. E. Demidov; Igor Barsukov; A. P. Nosov; A. B. Rinkevich; K. Sobotkiewich; Xiaoqin Li; Jing Shi; Ilya Krivorotov; S. O. Demokritov
We experimentally study nanowire-shaped spin-Hall nano-oscillators based on nanometer-thick epitaxial films of Yttrium Iron Garnet grown on top of a layer of Pt. We show that, although these films are characterized by significantly larger magnetic damping in comparison with the films grown directly on Gadolinium Gallium Garnet, they allow one to achieve spin current-driven auto-oscillations at comparable current densities, which can be an indication of the better transparency of the interface to the spin current. These observations suggest a route for improvement of the flexibility of insulator-based spintronic devices and their compatibility with semiconductor technology.
Spintronics XI | 2018
Chad Warren; Pathikumar Sellappan; Mohammed Aldosary; Yasuhiro Kodera; Jing Shi; Javier E. Garay
Rare earth iron garnets (REIG’s) are important component materials in magnetic insulator based spintronics due to their low spin wave damping and electrically insulating properties. Yttrium iron garnet (YIG) has been the mainstay material because of its unusually low spin damping. However, YIG thin films thus far have in-plane magnetization. Recent studies on thulium iron garnet (TIG) thin films have demonstrated robust perpendicular magnetic anisotropy (PMA), however, spin damping in TIG films is significantly higher compared to YIG. It would be useful to have an insulating magnetic material that exhibits both low spin damping and robust, tunable PMA because of its potential for novel device configurations. In this study, we synthesized YIG-TIG solid solution powders across the compositional phase diagram and with different particle sizes using the polymeric steric entrapment technique in order to begin to decouple compositional effects from size and morphological effects. Powder characterization, including XRD, VSM, SEM and FMR techniques, was also performed to understand their magnetic behavior.
Physical review applied | 2017
Aryan Navabi; Cai Chen; Anthony Barra; Mohsen Yazdani; Guoqiang Yu; Mohammad Montazeri; Mohammed Aldosary; Junxue Li; Kin L. Wong; Qi Hu; Jing Shi; Gregory P. Carman; Abdon Sepulveda; Pedram Khalili Amiri; Kang L. Wang
Archive | 2016
Jing Shi; Junxue Li; Yadong Xu; Mohammed Aldosary; Chi Tang; Roger K. Lake
Bulletin of the American Physical Society | 2018
Aryan Navabi; Cai Chen; Anthony Barra; Mohsen Yazdani; Guoqiang Yu; Mohammed Aldosary; Junxue Li; Mohammad Montazeri; Kin L. Wong; Jing Shi; Greg P. Carman; Abdon Sepulveda; Pedram Khalili Amiri; Kang L. Wang